How to get all capabilities

First, create [all-capabilities] shortcode. Put this code in your theme’s functions.php:

function wpse_all_capabilities() {
    $out="<style>
.flex-columns {
    column-count: 4;
    column-gap: 3em;
    column-rule: 1px solid #000;
}        
</style>";
    $out .= '<p class="flex-columns">';
    $users = get_users();
    foreach ( $users as $user ) {
        if ( $user->caps['administrator'] ) {
            $allcaps = array_keys( $user->allcaps );
            foreach ( $allcaps as $cap ) {
                $out .= $cap . '<br>';
            }
            $out .= '</p>';
            return $out;
        }
    }
}
add_shortcode( 'all-capabilities', 'wpse_all_capabilities' );

Update: it is possible that Administrator has some capabilities removed, so we need to scan all users. Modified code follows:

function wpse_all_capabilities() {
    $allcaps = array();
    $out="<style>
.flex-columns {
    column-count: 3;
    column-gap: 3em;
    column-rule: 1px solid #000;
}
h2 {
    text-align: center;
    column-span: all;
}        
</style>";
    $out .= '<div class="flex-columns">';
    $out .= "<h2>All Possible Users' Capabilities<hr></h2><p>";
    $users = get_users();
    foreach ( $users as $user ) {
        $caps = array_keys( $user->allcaps );
        foreach ( $caps as $cap ) {
            if ( !in_array( $cap, $allcaps, true ) ) {
                $num = array_push( $allcaps, $cap );  
            }
        }
    }
    foreach ( $allcaps as $capability ) {
        $out .= $capability . '<br>';
    }
    $out .= '</p></div>';
    return $out;
}
add_shortcode( 'all-capabilities', 'wpse_all_capabilities' );

Now, you can use [all-capabilities] shortcode on your page.